Add filter to find documents with zero files inside

[vmario89]

Hi,

another small improvement would be a filter to find documents which do not contain files, so are displayed with "(0)" in the doc's tree view. For preparing documents which are going to be populated in the future, there will be no files inside a longer period of time. The filter quickly can find them. And tt would also help to find docs which were accidently left blank in the past.

regards, Mario

[vmario89]

add: maybe the filter could be done by typing in some integer value range (e.g. 0-2 or 1-5) to look for docs which contain the desired amount of files. If you have a lot of similar structured documents (maybe due automation) this filter could also help to find docs which do not fit that structure.